Vibrating device



Dec. 24, 1935. F TR TT R 2,025,318

VIBRATING DEVICE Filed March 2, 1934 2 Sheets-Sheet l W 2 q RE L; z m 32 Q I Eel m h h w iiii* l I s t?- Q Q N INVENTOR WALTER F. TROTTER MWQ'A TTORNE Y5 Dec. 24, 1935.

Filed March 2, 1954 2 Sheets-Sheet 2 A TTO E YJ Patented Dec. 24, 1935UNITED STATES PATENT OFFICE Claims.

This invention relates to a vibrating device or power hammer and moreparticularly to that type in which repeated blows are imparted to alongitudinally movable tool or anvil by impacts 5 of a striker memberwhich forms part of a hammer body which rotates continuously in the samedirection.

An object of the invention is to provide a hammer member of greater massthan has hitherto been practicable in a device free of objectionablevibration. This is accomplished by using the entire mass of therotatable body to deliver the blows, by keeping the mass of the hammermember substantially in centrifugal balance at all times, and byabsorbing the rebound from each impact in a manner to minimizevibration.

Another object of the invention is to provide a striker member which isdouble acting in effect, that is to say, is arranged to deliver twoblows during each complete rotation.

A further object of the invention is to provide in a rotatable hammermember a striker member having a plurality of striking portions movablerelative to the axis of rotation from inoperative to striking positionand arranged so that the rebound from an impact moves the activestriking part to inoperative position and the next striking part tostriking position.

The invention also contemplates means for absorbing striker rebound in aradial direction when a blow is struck and cushioning the same by anoppositely acting centrifugal force, means for rotating a hammer memberby forces equally distributed about the axis of rotation, and other 86novel features which will appear from the accompanying description anddrawings.

In the drawings, Fig. 1 is a sectional view along the line l--l of Fig.2, showing a longitudinal view of my improved hammer, together with 40motor driving means therefor; Fig. 2 is a transverse sectional viewalong the line 22 of Fig. 1 showing the anvil fully advanced and beforerecession of the striker; Fig. 3 is a section similar to Fig. 2 showingthe striker fully withdrawn;

45 Fig. 4 is a detail view showing the position of the parts at theinstant of impact; while Fig. 5 is a view similar to Fig. 3 showing amodified form of striker member.

My invention comprises in general a rotatable 50 hammer'membe r andsuitable motor means for rotating the same continuously'in onedirection. A frame or casing serves to completely house these parts. Thehammer member comprises astriker and a carrier therefor. The carrier is55 slotted transversely and the striker is arranged for limitedreciprocating motion in the slot diametrically of the carrier to producealternate striking positions of its two striking parts. An anvil memberor tool is supported for reciprocation inthe frame with one end normallyheld 5. in the path of the rotating striker when the latter is in itsstriking position. The blows are delivered by the entire mass of therotating hammer member acting through the striker. The hammer member isof sufficient mass and is ro- 1O tated at suitable speed to deliver therequired blow when the striker impacts the anvil member. My improvedhammer member provides the maximum impact possible in a given size ofrotating hammer because the entire rotating mass de- 15 livers the blow.The striker is movable radially or diametrically of the carrier betweenits advanced striking and its retracted positions. It is arranged to beheld in its outer or striking position by centrifugal force acting uponthe 20 striker with a force dependent upon the mass of the striker andits radius of gyration. Upon impacting the anvil member the strikerrebounds and the parts are so arranged that the rebound takes place in aradial direction toward the axis 25 of rotation of the hammer. Twoadvantageous results follow. First, there is little or no tangential orrotative effect caused by the rebound of the striker. In certain typesof rotating hammers now used the rebound of the striker causes 30 arotative effect opposed to the rotation caused by the driving connectionof the tool, which unbalances the tool and greatly reduces the velocityof the rotating hammer. Second, the centrifugal force is acting radiallyoutwardly on the striker at the moment of impact, Whereas the reboundacts radially inwardly. Thus the rebound is cushioned and is retarded bythe effect of centrifugal force acting on the striker.

The striker might extend from the center of the carrier outwardly inonly one direction so as to deliver but one blow per revolution. Iprefer, however, to extend the striker diametrically across the carrier,as shown, and to limit its movement on each side of the axis ofrotation. The reaction from the blow delivered by one end causes thestriker to rebound so that the end which has just delivered an impactrecedes to non-striking position, while simultaneously the opposite endis advanced to striking position. The tool thus delivers two blows perrevolution. The parts are so arranged that striker rebound takes placeradially inwardly, as mentioned above. During the first part of thisstriker movement centrifugal force acts on the striker with respect tothe axisrof rotation is small, the striker never develops sufficientmomentum on.

this outward movement to cause appreciable jar.

In the form illustrated, the armature lb of an electric motorand acarrier l l are rigidly mount-- ed upon a common shaft I2. Suitableelectrical conductors" l3 provide current for the operation of themotor. The parts are conveniently housed. by means of casing member I4surrounding the motor, casing member l5 surrounding the carbers ofrotary tools of similar types.

rier and a partition member 16 separating the two casings, all of theseparts being suitably secured together, as for instance by means ofbolts, not shown. The shaft l2 may be supported for rotation inthecasing members, as by means of bearings Hand l8. r

The carrier is in centrifugal balance and in the form shown iscylindrical. It is provided with a transversely extending slot [9extending entirely through the carrier from side to side. Within thisslot a striker 20 is supported for reciprocation diametrically acrossthe carrier. The sides. of the striker conform to the sides of the slotopening through the carrier soas to provide a sliding fit. The strikeris relatively long and wide, thus providing a large mass of: metalcompared tothat usually found in the striker mem- In the embodimentshown the width of the striker is well over half the diameter of thecylindrical carrier. The movement of the striker transversely in itsslot is limited by contact with a portion of the carrier or a partmovable therewith. In the instant case, the striker has a centralopening 2| through which the shaft l2 passes, there being slight playbetween the sides of the opening and the shaft to permit endwisemovement of the striker. .The center of gravity of the striker is thusshifted slightly from one side of the axis of the shaft to the othereach time a. blow is delivered.

The striker has a relatively large mass but the V arrangement is suchthat the apparatus as a wciency and reducing the loss due to friction, Iprefer to form the striker member as shown in Figs. '1 to 4 in whichrollers 23 are inserted in slots 24 in'each end of the striker withsuitable bear ings 25 secured to the side walls of the slotsin a mannerto provide a free running roller. Thus the rollers. project slightlybeyond the arcuate ends of the hammer member in position to contact theanvil member 21.

If the device is to be used as a vibrator the striker member will bearranged to deliver a blowto somepart to be vibrated. I have illustratedsimply a blow-deliveringtool 25 having an anvil portion 2? and supportedin the frame or casing for reciprocation. The portion of the framesurrounding the blow-delivering member may be lined with anti-frictionmetal 28 and a retaining member or plate 29 may be arranged to preventthe member falling out of the frame. It will be noted that the path ofthe reciprocating anvil portion lies intermediate a radius and a tangentto the circular path of travel of the impact-delivering end of thestriker.

The rotation of the carrier and striker member is counter-clockwise asviewed in Figs. 2 to 5. The position of the striker at the instant ofimpact is shown in Fig. 4. The curved surface of roller 23 exerts acamming action on member 21. At the same time roller 23 is moving towardmember 21 due to its arc of travel about the axis of hammer rotation.Thus a glancing blow is struck which does not greatly reduce the speedof rotation of the hammer. Figs. 2 to 4 illus hate the positioning ofthe parts so that rebound takes place substantially in a radialdirection. In Figs. 2 and 4 it willbe noted that the center of gravityof the striker is on that side of the shaft axis on which the blow isbeing struck. The

rebound of the striker carries the. center of grav ity past the axis ofthe rotating shaft into the position indicated in Fig. 3, where theopposite end of the striker is in position to deliver a blow upon theadditional rotation of the carrier It will be obvious that centrifugalforce tends to maintain the striker in either of its extended positionsafter the striker is placed in one of those positions. That is to say,as the striker moves from the position of Fig. 2 to the position of Fig.

3, until the center of gravity of the striker coincides with the axis ofrotation, centrifugal force opposes the movement and softens therebound, while after the center of gravity of the striker has passed theaxis of the shaft, centrifugal action tends to carry the striker towardthe position of Fig. 3 and to hold it there until the opposite end ofthe striker has delivered a blow to the anvil whereupon the reboundagain reverses the center of gravity of the striker with respect to theshaft axis.

Upon the delivery of a blow the hammer is slightly retarded andacceleration is provided by the application of forces equallydistributed about the axis of rotation. The application of these forcesmay berepresented by the arrows F1 and F2 in Figs. 3 and 5 and it willbe noted that these forces form a balanced couple about the centralshaft which avoids any unbalanced effect which would occur if such forcewere applied at one side only of the rotating shaft.

Two advantages result from the construction of the double acting hammeras shown. In the first place, two impacts are obtained every revolution.In the second place, the energy of the rebound is used to position thestriker for the succeeding impact. In strikers having'but one hittingposition it is necessary to reverse the natural direction of the reboundto position the striker member for the following impact. It results,therefore, that my hammer efliciently conserves energy in utilizing thepower of rebound in the manner described. 7 Y Y 7 The kinetic energy ofa moving body varies directly as its mass times the square of itsvelocity.

The. mass of my improved hammer includes substantially the entireassembly of rotating parts comprised within the substantiallycylindrical casing enclosing the said parts. That is tosay. the mass ispractically the maximum which can be placed in a given casing. Thishammer is rotated at high velocity. Each blow is a glancing blow,accompanied by a rebound or recession of the striking member. Thevelocity of the rotating mass is only slightly retarded and hence a highkinetic energy is always maintained. This is due to the fact that theparts are so arranged that the center of gravity of the striker at themoment of impact is angularly in-advance of a radius connecting the axisof rotation and the point of impact between the striker end and theanvil member. I

At the same time, the power of the actuating motor is conserved becausethe striker and its carrier form a substantially centrifugally balancedrotating mass. The carrier element is for all practical purposes inabsolute balance without the use of any counter-weight and the strikermoves but slightly out of balance during the use of the tool. Thisstructure contributes to uniformity of rotation at high speeds withoutjolting or jarring of the shafts or bearings. The parts are so arrangedthat the path of travel of the striker diametrically across the carrierat the moment of impact is angularly in advance of a radius connectingthe axis of rotation and the point of impact between the striker end andthe anvil member. 7

The apparatus comprises few parts and is cheaply constructed as thehammer enclosing casing is substantially an unobstructed cylinder andthe carrier and the striker are of simple form and not easily broken.

Another advantage of the double acting striker is that it provides agreat number of impacts while holding the central shaft to aconservative number of revolutions.

What I claim is:

1. In a device of the class described, the combination of a frame, acarrier rotatable therein, means for continuously rotating said carrier,an anvil member supported for reciprocation in said frame and having aportion adapted to lie adjacent the periphery of the rotating carrier, arigid striker having two impact-delivering ends, means supporting saidstriker on said carrier for movement in a definite path diametricallyacross said carrier, means limiting said striker movement to positionits center of gravity a short distance each side of the axis of rotationof said carrier, whereby to present said impact-delivering endsalternately in position to impact said anvil portion, and said strikerand anvil portion being so 5 arranged that the rebound of said strikerwhen one end impacts said anvil portion moves the other end of saidstriker into impact-delivering position.

2. In a device of the class described, the combination of a frame, ashaft rotatable therein, means for continuously rotating said shaft, arigid striker having two impact-delivering ends, means mounting saidstriker for rotation with said shaft and for free movement in a singlepath diametrically across said shaft axis, means limiting said movementto position the center of gravity of said striker a short distance onopposite sides of the axis of said shaft, an anvil member supported forreciprocation in said frame, said anvil member having a portion adaptedto lie in the path of that end of said striker lying on the same side ofthe shaft center as the center of gravity of said striker, and saidstriker and mounting means and anvil member being so arranged that therebound of said striker when' one end impacts said anvil portion movesthe other end of said striker into impact-delivering position.

3. A device as in claim 2, in which said anvil member is supported forreciprocation in a path intermediate a radius and a tangent to thecircular path of travel of the impact-delivering end of said striker.

4. A device as in claim 2, in which the parts are so arranged that thecenter of gravity of said striker at the moment of impact is angularlyin advance of a radius connecting said axis of rotation and the point ofimpact between said striker end and said anvil member.

5. A device as in claim 2, in which the parts are so arranged that saidstriker path at the moment of impact is angularly in advance of a radiusconnecting said axis of rotation and the point of impact between saidstriker end and said anvil member.

WALTER F. TRO'II'ER.

